The overall goal of this project is to define previously undescribed risk factors affecting birth outcome from pregnant women in the following ethnic groups: American Blacks, Chinese, Mexican- American, Puerto Ricans, and Whites. These groups are known to differ in their rates of low birth weight. An extensive questionnaire is under development to explore the cultural, psycho-social, nutritional and other differences among pregnant women from these groups. Pretesting of the interview instruments will take place in the summer of 1987 and interviewing is scheduled to begin in New York and Chicago in the fall. Approximately 200-400 pregnant women in each group will be enrolled and followed to delivery.